kimi_vl.py

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# ruff: noqa: E501
# Adapted from https://huggingface.co/moonshotai/Kimi-VL-A3B-Instruct/blob/main/modeling_kimi_vl.py
# Copyright 2025 The Moonshot AI Team, DeepSeek-AI, and HuggingFace Inc. team. All rights reserved.
#
# The code is based on llava (llava/modeling_llava.py) and DeepSeek-V3 (DeepSeek-V3/modeling_deepseek.py), but modified for KimiVL.
#
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# - Code derived from llava (llava/modeling_llava.py) and DeepSeek-V3 (DeepSeek-V3/modeling_deepseek.py) is licensed under the Apache License, Version 2.0.
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import math
from collections.abc import Iterable, Mapping, Sequence
from dataclasses import dataclass
from typing import Annotated, Any, Literal

import torch
from torch import nn
from transformers import BatchFeature
from transformers.activations import GELUActivation

from vllm.config import VllmConfig
from vllm.config.multimodal import BaseDummyOptions
from vllm.model_executor.layers.linear import ReplicatedLinear
from vllm.model_executor.models.interfaces import SupportsMultiModal, SupportsPP
from vllm.model_executor.models.moonvit import MoonVitPretrainedModel
from vllm.multimodal import MULTIMODAL_REGISTRY
from vllm.multimodal.inputs import (
    MultiModalDataDict,
    MultiModalFieldConfig,
    MultiModalKwargsItems,
    NestedTensors,
)
from vllm.multimodal.parse import (
    ImageEmbeddingItems,
    ImageProcessorItems,
    MultiModalDataItems,
)
from vllm.multimodal.processing import (
    BaseDummyInputsBuilder,
    BaseMultiModalProcessor,
    BaseProcessingInfo,
    PromptReplacement,
    PromptUpdate,
)
from vllm.sequence import IntermediateTensors
from vllm.transformers_utils.configs import KimiVLConfig, MoonViTConfig
from vllm.utils.tensor_schema import TensorSchema, TensorShape

from .utils import AutoWeightsLoader, init_vllm_registered_model, maybe_prefix
from .vision import run_dp_sharded_mrope_vision_model


# For dummy input only
@dataclass
class MaxImageTokenMeta:
    width: int = 1024
    height: int = 1024


class KimiVLMultiModalProjector(nn.Module):
    def __init__(
        self, config: KimiVLConfig, use_data_parallel: bool = False, prefix: str = ""
    ):
        super().__init__()
        self.use_data_parallel = use_data_parallel

        self.hidden_size = (
            config.vision_config.hidden_size
            * config.vision_config.merge_kernel_size[0]
            * config.vision_config.merge_kernel_size[1]
        )

        self.pre_norm = torch.nn.LayerNorm(config.vision_config.hidden_size, eps=1e-5)
        self.linear_1 = ReplicatedLinear(
            self.hidden_size,
            self.hidden_size,
            bias=True,
            prefix=maybe_prefix(prefix, "linear_1"),
        )
        self.linear_2 = ReplicatedLinear(
            self.hidden_size,
            config.text_config.hidden_size,
            bias=True,
            prefix=maybe_prefix(prefix, "linear_2"),
        )
        self.act = GELUActivation()

    def forward(self, image_features: torch.Tensor) -> torch.Tensor:
        hidden_states = self.pre_norm(image_features).view(-1, self.hidden_size)
        hidden_states, _ = self.linear_1(hidden_states)
        hidden_states = self.act(hidden_states)
        hidden_states, _ = self.linear_2(hidden_states)
        return hidden_states


class KimiVLImagePixelInputs(TensorSchema):
    """
    Dimensions:
        - nc: Number of channels
        - np: Number of patches
        - ps: Patch size
        - ni: Number of images
    """

    type: Literal["pixel_values"] = "pixel_values"

    pixel_values: Annotated[
        torch.Tensor | list[torch.Tensor],
        TensorShape("np", 3, "ps", "ps"),
    ]

    image_grid_hws: Annotated[torch.Tensor, TensorShape("ni", 2)]


# TODO: support embeds too
# We only support pixel input for kimi-vl now
KimiVLImageInputs = KimiVLImagePixelInputs


class KimiVLProcessingInfo(BaseProcessingInfo):
    def get_hf_config(self):
        return self.ctx.get_hf_config(KimiVLConfig)

    def get_supported_mm_limits(self) -> Mapping[str, int | None]:
        return {"image": None}

    def get_num_image_tokens(
        self,
        *,
        image_width: int,
        image_height: int,
    ) -> int:
        hf_processor = self.get_hf_processor()
        patch_size = hf_processor.image_processor.patch_size
        kernel_size = hf_processor.image_processor.merge_kernel_size
        in_token_limit = hf_processor.image_processor.in_token_limit
        height = image_height
        width = image_width
        assert isinstance(height, int), f"height must be int, current height {height}"
        assert isinstance(width, int), f"width must be int, current width {width}"
        assert kernel_size is not None, "kernel_size must be specified"

        if (width // patch_size) * (height // patch_size) > in_token_limit:
            scale = math.sqrt(
                in_token_limit / ((width // patch_size) * (height // patch_size))
            )
            new_w, new_h = int(width * scale), int(height * scale)
            width, height = new_w, new_h

        kernel_height, kernel_width = kernel_size

        pad_height = (
            kernel_height * patch_size - height % (kernel_height * patch_size)
        ) % (kernel_height * patch_size)
        pad_width = (
            kernel_width * patch_size - width % (kernel_width * patch_size)
        ) % (kernel_width * patch_size)

        # Calculate new dimensions after padding and patching
        token_height = (height + pad_height) // (kernel_size[0] * patch_size)
        token_width = (width + pad_width) // (kernel_size[1] * patch_size)
        return int(token_height * token_width)

    @property
    def image_token_id(self) -> int:
        return self.get_hf_config().media_placeholder_token_id


class KimiVLDummyInputsBuilder(BaseDummyInputsBuilder[KimiVLProcessingInfo]):
    def get_dummy_text(self, mm_counts: Mapping[str, int]) -> str:
        num_images = mm_counts.get("image", 0)

        processor = self.info.get_hf_processor()
        image_token = processor.image_token

        return image_token * num_images

    def get_dummy_mm_data(
        self,
        seq_len: int,
        mm_counts: Mapping[str, int],
        mm_options: Mapping[str, BaseDummyOptions] | None = None,
    ) -> MultiModalDataDict:
        num_images = mm_counts.get("image", 0)

        image_overrides = mm_options.get("image") if mm_options else None

        return {
            "image": self._get_dummy_images(
                width=MaxImageTokenMeta.width,
                height=MaxImageTokenMeta.height,
                num_images=num_images,
                overrides=image_overrides,
            )
        }


class KimiVLMultiModalProcessor(BaseMultiModalProcessor[KimiVLProcessingInfo]):
    def _get_mm_fields_config(
        self,
        hf_inputs: BatchFeature,
        hf_processor_mm_kwargs: Mapping[str, object],
    ) -> Mapping[str, MultiModalFieldConfig]:
        image_grid_hws = hf_inputs.get("image_grid_hws", torch.empty((0, 2)))
        image_grid_sizes = image_grid_hws.prod(-1)

        # pixel_values is merged as a single large tensor
        # image_grid_hws is shapes for each subtensor in pixel_values
        return dict(
            pixel_values=MultiModalFieldConfig.flat_from_sizes(
                "image", image_grid_sizes
            ),
            image_grid_hws=MultiModalFieldConfig.batched("image"),
        )

    def _get_prompt_updates(
        self,
        mm_items: MultiModalDataItems,
        hf_processor_mm_kwargs: Mapping[str, Any],
        out_mm_kwargs: MultiModalKwargsItems,
    ) -> Sequence[PromptUpdate]:
        image_token_id = self.info.image_token_id

        def get_replacement(item_idx: int):
            images = mm_items.get_items(
                "image", (ImageEmbeddingItems, ImageProcessorItems)
            )

            if isinstance(images, ImageEmbeddingItems):
                num_image_tokens = images.get_feature_size(item_idx)
            else:
                image_size = images.get_image_size(item_idx)
                num_image_tokens = self.info.get_num_image_tokens(
                    image_width=image_size.width,
                    image_height=image_size.height,
                )

            return [image_token_id] * num_image_tokens

        return [
            PromptReplacement(
                modality="image",
                target=[image_token_id],
                replacement=get_replacement,
            ),
        ]


@MULTIMODAL_REGISTRY.register_processor(
    KimiVLMultiModalProcessor,
    info=KimiVLProcessingInfo,
    dummy_inputs=KimiVLDummyInputsBuilder,
)
class KimiVLForConditionalGeneration(nn.Module, SupportsMultiModal, SupportsPP):
    supports_encoder_tp_data = True

    @classmethod
    def get_placeholder_str(cls, modality: str, i: int) -> str | None:
        if modality.startswith("image"):
            return "<|media_start|>image<|media_content|><|media_pad|><|media_end|>"

        raise ValueError("Only image modality is supported")

    def __init__(
        self,
        vllm_config: VllmConfig,
        prefix: str = "",
    ) -> None:
        super().__init__()
        model_config = vllm_config.model_config
        config: KimiVLConfig = model_config.hf_config
        quant_config = vllm_config.quant_config

        self.config = config
        self.quant_config = quant_config

        assert isinstance(config.vision_config, MoonViTConfig)
        self.use_data_parallel = (
            model_config.multimodal_config.mm_encoder_tp_mode == "data"
        )
        self.hidden_size = config.text_config.hidden_size

        with self._mark_tower_model(vllm_config, "image"):
            self.vision_tower = MoonVitPretrainedModel(
                config.vision_config,
                prefix=maybe_prefix(prefix, "vision_tower"),
            )
            self.multi_modal_projector = KimiVLMultiModalProjector(
                config=config,
                use_data_parallel=self.use_data_parallel,
                prefix=maybe_prefix(prefix, "multi_modal_projector"),
            )

        with self._mark_language_model(vllm_config):
            self.language_model = init_vllm_registered_model(
                vllm_config=vllm_config,
                hf_config=config.text_config,
                prefix=maybe_prefix(prefix, "language_model"),
                architectures=["DeepseekV2ForCausalLM"],
            )

        self.make_empty_intermediate_tensors = (
            self.language_model.make_empty_intermediate_tensors
        )

        self.media_placeholder: int = self.config.media_placeholder_token_id

    def _parse_and_validate_image_input(
        self, **kwargs: object
    ) -> KimiVLImageInputs | None:
        # image input type must be pixel values now
        pixel_values = kwargs.pop("pixel_values", None)
        image_grid_hws = kwargs.pop("image_grid_hws", None)

        if pixel_values is None:
            return None

        return KimiVLImagePixelInputs(
            type="pixel_values",
            pixel_values=pixel_values,
            image_grid_hws=image_grid_hws,
        )

    # perform vt on processored pixel_values
    @torch.inference_mode()
    def _process_image_pixels(self, inputs: KimiVLImagePixelInputs) -> torch.Tensor:
        pixel_values = inputs["pixel_values"]
        image_grid_hws = inputs["image_grid_hws"]
        if self.use_data_parallel:
            return run_dp_sharded_mrope_vision_model(
                self.vision_tower,
                pixel_values,
                image_grid_hws.tolist(),
                rope_type="rope_2d",
            )
        else:
            return self.vision_tower(pixel_values, image_grid_hws)

    def _process_image_input(self, image_input: KimiVLImageInputs) -> torch.Tensor:
        assert image_input["type"] == "pixel_values"
        image_features = self._process_image_pixels(image_input)
        assert isinstance(image_features, (list, tuple))
        lengths = [x.shape[0] for x in image_features]
        return self.multi_modal_projector(torch.cat(image_features)).split(lengths)

    def embed_multimodal(self, **kwargs: object) -> NestedTensors | None:
        # Validate the multimodal input keyword arguments
        image_input = self._parse_and_validate_image_input(**kwargs)
        if image_input is None:
            return None

        # Run multimodal inputs through encoder and projector
        vision_embeddings = self._process_image_input(image_input)
        return vision_embeddings

    def forward(
        self,
        input_ids: torch.Tensor | None,
        positions: torch.Tensor,
        intermediate_tensors: IntermediateTensors | None = None,
        inputs_embeds: torch.Tensor | None = None,
        **kwargs: object,
    ) -> IntermediateTensors:
        if intermediate_tensors is not None:
            inputs_embeds = None

        hidden_states = self.language_model(
            input_ids=input_ids,
            positions=positions,
            intermediate_tensors=intermediate_tensors,
            inputs_embeds=inputs_embeds,
        )

        return hidden_states

    def compute_logits(self, hidden_states: torch.Tensor, **kwargs) -> torch.Tensor:
        return self.language_model.compute_logits(hidden_states)

    def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]):
        loader = AutoWeightsLoader(self)
        return loader.load_weights(weights)